#include<stdio.h>
#include<unistd.h>
int g_val=100;
int main()
{
    pid_t id = fork();
    if(id==0)
    {
        //child
        int i=0;
        while(1)
        {
             
            printf("i am child,pid:%d,ppid:%d,g_val:%d,&g_val:%p\n",getpid(),getppid(),g_val,&g_val);
            sleep(1);
            i++;
            if(i==5)
            {
                g_val=200;
                printf("child change g_val:100->200,g_val:%d\n",g_val);
            }

        }
    }
    else if (id>0)
    {
        //father
        while(1)
        {
            printf("i am father,pid:%d,ppid:%d,g_val:%d,&g_val:%p\n",getpid(),getppid(),g_val,&g_val);
            sleep(1);
        }
    }
    else
    {
        printf("进程创建失败\n");
    }
    return 0;
}

